Nuclear quantum effects on the high pressure melting of dense lithium.
J Chem Phys
; 142(6): 064506, 2015 Feb 14.
Article
em En
| MEDLINE
| ID: mdl-25681922
ABSTRACT
Using a self-developed combination of the thermodynamic integration and the ab initio path-integral molecular dynamics methods, we quantitatively studied the influence of nuclear quantum effects (NQEs) on the melting of dense lithium at 45 GPa. We find that although the NQEs significantly change the free-energies of the competing solid and liquid phases, the melting temperature (Tm) is lowered by only â¼15 K, with values obtained using both classical and quantum nuclei in close proximity to a new experiment. Besides this, a substantial narrowing of the solid/liquid free-energy differences close to Tm was observed, in alignment with a tendency that glassy states might form upon rapid cooling. This tendency was demonstrated by the dynamics of crystallization in the two-phase simulations, which helps to reconcile an important conflict between two recent experiments. This study presents a simple picture for the phase diagram of lithium under pressure. It also indicates that claims on the influence of NQEs on phase diagrams should be carefully made and the method adopted offers a robust solution for such quantitative analyses.
Texto completo:
1
Base de dados:
MEDLINE
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article